How Not to Keep a Secret
by DilynAliceBlake
Summary: Tony is a Mermaid (but don't let him hear you say that.) Much as he would like this little bit of trivia kept under wraps, when a heat is mistaken for a fever the Avengers decide a dunk in the bathtub is the way to go. Before he can get very far at propositioning Steve or threatening Natasha some guy crashes down in New Mexico claiming to be Thor. It gets more convoluted from there
1. Chapter 1

A/N: Please disregard cannon completely. I took quite a bit of creative license, but don't fret. Thor and Loki will appear eventually.

Tony Stark avoided the water. Not the small, every day amounts like rain or what went into coffee. He avoided submerging himself in bodies of water. Once it was deep enough that standing it would reach his knees he gave it a wide berth. Because whenever Tony was in water like that, he grew a tail.  
Tony didn't like to use the term merperson. It didn't exactly bring to mind curved black talons, molten scotch eyes, scales, webbing, and rows of pointed teeth. So, since Tony was a badass aquatic predator, and not a singing Disney monstrosity, he preferred referring to himself as a sea dragon. Sure, he didn't have wings, but he thought that the cool growling and hissing noises he could make more than made up for that.

Whenever Tony was being a totally bitchin sea dragon he got to have stunningly bold crimson scales, and nice contrasting yellow accents on the fins. At first he had been a little bummed at the lack of camouflage, but then he had realized that sea creatures probably had different cones in their eyes, and for all he knew he blended in perfectly well with the spectrum of colors through which they viewed the world. Tony also thought that maybe he was high enough up on the food chain not to need camouflage.  
Oh, and get this, he also got horns. Sure, they were kind of small, maybe only an inch high, and about the same diameter at the base, but since the were the same bold red as his scales, also tipped in that bright gold, any bigger would likely be ostentatious. Besides, the amount of times he had referred to himself as horny for the play on words alone made them worthwhile in his book. Tony had wondered why they weren t the black-with-red-shine of his claws, until he realized that his hair was that colour instead of its usual (boring) human auburn, and he thought that the horns were cooler without blending in with his curls.  
It was pretty awesome, being part water serpent dragon thing, right up until he realized that if his legs weren t submerged he was still just as capable of drowning as anyone else. And wasn t that just a hoot and a half, being water boarded in some cave and realizing, hey, no gills, claws, not even that nifty second eyelid, and was this what swimming was like for regular people, because it sucked.

Fast forward a bit to the suit. Okay, so he based the coloration off his scales, but can you blame him? It was so totally him.

Tony preferred to do his heroing with his brain and charisma. Like a normal guy, except, you know, not. Just your average billionaire playboy philanthropist, except with fins on the side. If you can t take his word for it go ahead and ask Bruce Wayne how he liked to spend his spare time. Yeah, see? Maybe they could start a club.

He got the scale thing from his mother, of that much Tony is sure. He knows he was a water birth, and has a few blurry memories of being very small and her hand with red claws and pale silvery pink and cr me scales stirring bubbles in his bath water. Other than that, the topic of being part fish was rather studiously avoided in the Stark household. Tony doesn t even think that his father knew. Maybe if Howard Stark had realized what a good potential experiment Tony was he wouldn t have gotten so wound up over the loss of the good captain. Maybe if he had been sober more often he would have realized that his wife and son could grow gills.

It was irrelevant at this point. There was a rather urgent matter at hand. Tony didn t want Shield experimenting on him any more than he had fancied the idea of his father doing so, so he d made up some lie about water pressure and the Arc Reactor (as if) to avoid large bodies of water. Unfortunately all of that would be for naught if Clint succeeded in prying Tony away from his grip on the headboard and putting him into the bath that Natasha was currently drawing.

Tony, come on, we have to do something to break this fever! Geez, let go, why are your head boards so sturdy? Tony snickered, glancing toward Steve, who was standing by awkwardly in the corner of his bedroom to see if his assistance would be needed. Apparently Captain Rogers got the joke, because a few seconds later he was red as a beet paying even more studious attention to the floor, regardless of the fact that Barton s question had been rhetorical and not at all in the dirty double entendre spirit.

When, what seemed like ages past, Agent Coulson had suggested a team of super heroes to Tony, he had been all for it, even going so far as to suggest Stark Tower as a base. Fury didn t trust Tony as far as he could throw him, but even the pompous Cyclops himself saw the advantage of having a billionaire genius weapons designer on the same team as his personal pet assassins. Tony had no doubt that part of the reason the two Shield puppets were staying at the Tower was to keep an eye on him. Still, it had been pretty cool, meeting all the candidates as Agent rounded them up.

This, though, this was potentially a problem.

"Shower, Katniss, shower! I ll let go if you promise not to plop me into a tub full of water. I don't take baths." He tried to bargain with his harrassers. Bruce, who was passing through Tony's room with a tray of medical supplies on the way to the master bath, sent a sympathetic glance his way. Natasha s voice came through the door in an impatient bark. "Stark, if you don t take baths then why the hell is your tub is the size of a swimming pool and your bathroom bigger than your bedroom?"

"Shut up Nat, nobody asked for your opinion! I don't want a bath, I refuse! The fever will go away on its own, and SO SHOULD ALL OF YOU!" Natasha strode into the room, raising both eyebrows at the sight of Tony holding his own in a battle of grips and wills against the arrowmaster.

"Rogers." She tilted her head towards Steve, then towards Tony to indicate that it was time to bring in more-than-human-strength. Steve apologetically, but obligingly began making his way towards the bed. Tony abruptly and simultaneously let go of the bedpost and twisted to the side, flinging himself out of Clint s grip and to the floor. He scrambled backwards frantically.

"No, no, no, please, no, no," Tony chanted, trying to get away from Tall, Blonde, and Daunting.

As a child all the attention that Tony s father might have had for him was already delegated between being blindingly drunk and finding the supposedly perfect lost soldier. After telling himself that he had grown out of that infatuation, seeing that Steve was everything the childhood stories idolizing him to be and more, Tony had done his absolute utmost to avoid the Captain. That was an awkward crush if ever there was one, and Mr. Perfect luckily wasn t inclined to push boundaries and force a friendship when Tony had firmly established himself as the loner type. Because of this, it was only just now coming to light that he may have been avoiding Roger s in particular, and not just everyone except Bruce. That kind of averse reaction was out of character even for someone so unpredictable as Tony. Suddenly, Natasha looked a lot more intrigued than was good for Tony s health.

Steve bit his lip, creeping a little closer, but seeming unsure at the sudden increased violence of Tony's refusal. He glanced to Tasha for guidance. "I don't want to hurt him."

"Stark, stop being childish. You re probably delirious with fever. Let Cap carry you, and you can have a shower instead of a bath."

Tony eased to a stop at those words from Widow, visibly calming. Steve scooped him up into a strong grip and took him into the bathroom, everyone else filing in after. Once Tony saw the tub full of bathwater, however, he resumed his tantrum, kicking and shouting with a vengeance. "No! You sneaky evil spy BETRAYER! Liar! You are a lying liar who tells dirty, filthy, lies! Jarvis, lockdown code Dragonhunter-X-4-7, I want all electronic signals cut, no one in or out except for me and Bruce. Knock out Shield s power so they don't suspect anything for a bit."

"Right away, Sir. Shall I put in an order for Sushi and add the appropriate salts to the bath while I m at it?" The A.I. queried.

"Sure thing, Jarv. You guys want anything? Well that's too bad because lying liars don't get treats. Brucey, you're free to go at any time, but I might need you on my side in a bit."

Natasha frowned down at the phone she was holding in one hand (the other occupied leveling a gun at Tony), undoubtedly having tried it once her earpiece relayed nothing but static. Steve looked wary, Clint irritated, and Bruce still seemed surprised that, whatever was going on, Tony trusted him enough to give him access to the doors.  
Tony rolled his eyes. "Oh, come on Brucey, whatever goes down, I know you of all people aren't going to give me over for Shield's science department to prod at." Natasha went from confidently laidback assassin mode to full attention zeroed in on Stark. "Whatever this is, it s deeper than a fear of water." She narrowed her eyes at him. "What's going on? What are you hiding, Mr. Stark?

Tony frowned. "Dammit, you had records on the torture, I should have went with the 'Scared of Water' angle." Suddenly Steve s posture shifted to one of authority and outrage, Captain America s morals shining through. "He had an experience involving water torture and you wanted me to throw him into a bath? Why don t you just stick me in a freezer?!"

Huh, it seems if he played this right Tony could get Rogers on his side too.

Steve cleared his throat. "Um, Tony, why exactly did you feel the need to lock us all in here?"

Natasha's smug and expectant smirk was not all endearing him to her.

"There are two options here, Boy Scout." Tony tried not to get distracted by the fact that he was still being held bridal style against Steve's chest as if he were weightless. "Option one, you all take my word on the fact that I m. Not. Sick. Hangover, lack of sleep, write it off however you want, it will resolve itself. Return me to my bed, and we can all forget that this little escapade ever happened. Or, you can continue with this monumental breach of privacy, in which case you need to get comfortable, because you aren t going anywhere until I m satisfied with how the matter has been sorted." Tony settled himself casually in Steve s arms to wait while they decided, taking advantage of the proximity to breath in Steve s scent, like drawing charcoal and leather and (unsurprisingly) seawater.

Clint and Steve spoke at the same time, Clint with an irritated "What matter? Nothing has-" and Steve with a confused "Breach of privacy? Tony, you're already naked, what more could-"

Tony growled. Unfortunately, they must have been close enough to his enormous tub for his body to sense the water, because he had enough access to his dragon vocal chords for it to come out as a growl, the deep rumble echoing through his chest enough to startle Steve into dropping him. He landed with a splash into the water, and for the first few moments tried to scramble to get out before

Tony stilled and let out a resigned sigh when he felt his skin tighten and prickle. He closed his eyes and laid back, nothing to do now but accept the situation and deal with the aftermath.

When he first surfaced Bruce seemed to think it was finally time to make his say. "Tony, I don t understand why you re so against this. I ve looked at the schematics for the Arc Reactor, and even if the water were deep enough-" Bruce stopped talking. The room was dead silent, all eyes on Tony. He opened molten golden eyes and viewed the room through new perspective.

Each face came with a rush of ideas and emotions connected, along with the name.  
Bruce; family, clan, ally, strong, friend. A mental flash of an angry green beast to go with that.  
Clint; weak, arrogant, prey. A thought of enemy clan followed by a mental image of Natasha and Fury.  
Natasha; threat, scared, dangerous, enemy.  
And finally, Steve; strong, attractive, commanding, mate.

Of course his instincts had decided that. Tony had suspected since he had first discovered Steve Rogers was alive, and having the suspicions confirmed more solidly than just a desire to please and be noticed by the blond was hardly surprising. Any awkwardness that may have followed the realization was subverted by a natural trust in his instincts. Once he had assessed the room he kept his gaze trained on Natasha s gun.

Aimed to wound, but her hands were shaking. The smile Tony gave her was more a warning flash of his newly pointed teeth than anything. He lounged against the wall of the tub, swishing his tail lazily in front of him. It started just below his hip bones, and was several feet longer than his legs were. "Go ahead, Nat. Shoot me. Better aim to kill, though. The scales are bulletproof." She flinched, and mentally Tony conceded to himself that perhaps he was feeling a bit vindictive. He sighed.  
"Put the gun down, Tash, and let s talk about this like reasonable adults. Well, as reasonable as anyone in Shield s back pocket can be under the circumstances. And, okay, I ll be honest, my brain isn't being run exactly like a human's right now, but I can avoid violence so long as I don t feel threatened." Natasha looked less like a bundle of nerves having assessed that he was still in at least partial possession of his faculties.

"Sir." Jarvis chimed.

Tony shot Bruce a grin. "So, mean and green, be a doll and go get the sushi? I m sure it would make Tasha feel better to know that I m not hungry." Bruce quickly obliged, seeming relieved for a chance at a break from such a high tension situation.

Tony noticed Steve gazing at him with awe, hands twitching as if in want of a sketchpad, and failed at resisting the urge to preen. He stayed reclined casually against the edge of the tub (pool), keeping an eye on the room's occupants.

Natasha frowned, but eventually her curiousity won out against her need to remain stoic. "How did you know I was nervous?"

Tony gestured in her direction flippantly, though he knew that his offhandedness about the claws would do anything but put her at ease. "Your hands were shaking, and you just register as nervous. Same way Cap says leader and Clint says weak and arrogant."

Clint, apparently, took offense. "Hey, I m not-"

"Sorry," Tony stated, blatantly insincere, "You're too self assured, not on the alert at all. In a room with a predator, the unaware are the easiest prey."

Taking in Tony's appearance more carefully, then looking at Natasha, Clint seemed to realize that she had just admitted to being nervous. He took several steps back, intimidated by anything that had the nearly unshakable woman fearful.

Tasha stared at Tony. "If my hands were shaking it wasn't enough to be visible to the human eye." Suddenly she seemed intrigued. "When I was very young my mother told me of a serpent creature which could see into a person s soul and use what it found there to make them beg for death before granting it and feasting upon their heart. Shield could really-"

The door slammed open and Bruce stormed back into the room, loud and intimidating, while being cheerful and innocuous simultaneously. "Sushi! I brought Sushi for Tony. I also have Lo Mein, Teriyaki, and eggrolls."

Tony really hoped the look he gave Nat conveyed 'Your mother must have been sick in the head to tell a little girl such a seriously fucked up story and Ew, no, that's weird,' because talking over Bruce would have been rude. He thought that she was probably good enough a spy to get the gist of it, and while normally he wouldn't care about rudeness, Bruce had just saved him from a conversational landmine. And brought food. He would rather face the inevitable questions after he ate, which he now could because Bruce had brought him sushi.

After a few bites Tony decided that he didn t trust the look to have been enough after all. Don t worry, Spider Queen. "If I end up killing you I'll do it quickly. Also, there is absolutely no practicality in eating just your heart. What a waste." He made a hmm noise, considering the matter in a way he probably wouldn't have been comfortable with had he been entirely human. "Yeah, no. That s a lot of tearing to get at one little organ for something as petty as sentimental significance. No, I d go for the throat. Tearing with teeth is more fun anyway."

And because no one in the room was normal, Bruce seemed intrigued at his thought pattern, Cap seemed to accept that his normal rules of morality and right and wrong didn't apply to sea dragons, and Natasha just seemed relieved that he wouldn't guilt trip her into begging for mercy before feasting upon her heart. Which, really; What the actual fuck?!

Clint, of course, was scrambling rather hilariously farther away from Tony.

His crinkled his nose in distaste. "Dude, you wreak of fear. Chill." He speared a sushi roll on a claw, dipping it in sweet and sour sauce before popping it into his mouth. When he grinned at Clint, his teeth were stained red. He swiped his tongue over them slowly before returning to a semi-friendly expression. Natasha and Bruce both seemed amused. Steve, Tony turned his attention to the soldier, and suddenly flipped so that he was floating on his stomach, top half leaning out over the edge of the tub. He tried to squirm closer, harldly believing his own senses. (He gave an internal snort at the innuendo. Yeah, hardly.)

"Cap? I m surprised at you. You like the idea that I bite?" Tony was practically purring, voice low and inviting.

Steve suddenly seemed to remember that Tony could gauge their emotions with a glance, because he was instantly the picture of awkward. "I, no, um, just, you re very pretty, no wait, not-"

Tony smirked, gazing lazily through half lidded eyes. "Ooh, Steve," Tony made sure whisper the name breathily for maximum effectiveness, "Are you interested in a closer look at my scales? This is me formally inviting you to invesigate my teeth with your tongue." He opened his mouth into a suggestive 'O' and let Cap's mind take him where it may.

"I was never a boyscout." Steve blurted, still blushing.

Tony raised an eyebrow at the apparently ranodm outburst. Steve elaborated, "I just, um, thought you should know I am not the paragon of purity you all seem to think."

On the one hand Tony was upset that Steve had thought up a nickname for himself more catchy than the ones Tony had given him. On the other hand...Possibilities.


	2. Chapter 2

**A/N: I would like to apologize for the glitch where on the last chapter all the quotation marks and apostrophes just disappeared. That being said, I am not going to fix it any time soon.**

Agent Phil Couldson of Strategetic Homeland Intervention, Enforcement and Logistics Division, did not particularly _care_ that Tony Stark had, for some as-of-yet un-ascertained reason, hacked SHIELD's power board. Later, the paperwork for that incident was going to be a bitch to file. Currently? To be frank, he had bigger fish to fry.

Space anomaly sized fish. Possibly hostile alien viking sized fish. _He had not yet had time to pause for coffee_ sized fish. He sincerely hoped that Fury did not try and manipulate him today, because Coulson wasn't entirely sure that he'd be able to resist telling the Director where to shove it.

Norse gods, _sonnuvabitch_. At least his job was never boring.

He entered what Stark had informed him was an all access keycode and swept into Tony's main bedroom with his best 'authority face' on. Oh. It seemed he wouldn't have to hunt them each down in turn. Bruce Banner was awkwardly poking a pair of chopsticks into a carton of noodles. Clint looked rather queasy, his face pallid and his eyes flicking around nervously. Coulson didn't have time to determine if he was more scared or naseous. Natasha just looked thoughtful.

"If Stark is feeling better, get him, too. Someone fetch Rogers. Avengers Assemble, this is _not_ a drill. There is a Situation down in New Mexico, I'll brief you on the way. Domestic disputes can be put on hold."

Nat spoke first. "They're both in there," she cut her eyes towards the door to the bathroom, "It was conclusively determined that Iron Man is not sick. His fever was due to.., Other causes, which, at this juncture, we have agreed not to discuss. That having been said, I refuse to approach and take the risk of angering him."

Clint turned rather green. "Oh no, I am _not_ going in there again. I saw more than was safe, I saw more than I needed to, definately more than I _wanted_ to, already. Not being discriminatory here, just, no. There is not enough therapy in the world for that."

Bruce looked even more uncomfortable. "I...would rather not interrupt. Actually, me and the Other Guy have reached our tension limit." His face was flushed an awkward pink. "I'll certainly never look at Tony the same way again."

Coulson would, on any other occasion, have assessed the situation carefully, pressing for more information and trying to weedle something less vague about what had happened out of his team. Later, he would blame the high stress and lack of coffee for the fact that he just ignored no less than _seven_ potential Red Flags. Eight, once he started towards the bathroom and Jarvis warned him quite clearly that it was a bad idea.

The way things played out, he simply barged into the room.

The way things played out, he would likely be attending those therapy sessions with Barton.


	3. Chapter 3

Tony Stark was stunning. Steve Rogers had always leaned more towards art for self expression, and he knew that whatever words he may shove together, his description wouldn't do Tony justice.

Steve wondered when Stark had become _Tony_ in his head.

'_Jesus_,' he realized '_I'm oggling Howard's little boy_.'

The thought should have stopped him. It didn't.

'_Pay attention,_' he told his brain. Tony was saying something, but golly, he was just so beautiful...

Rats, he might have said that part out loud.

Tony was talking again, saying something about tearing someone's throat out, and really he should intervene, except his brain suddenly wasn't bothered by that at all. Apparently the addition of teeth had given his brain the go ahead to excuse Tony from the expectation of human decency.

'_Don't think about decency_,' he thought. '_Thinking about decency leads to thinking about indecency and really how was he expected to be able to get the texture of those scales down on paper without some up close investigation_?'

He'd have to touch them. For research. In the name of art. Possibly with his mouth. How sensitive were they? Bulletproof didn't necessarily mean that they couldn't _feel_...

Steve's brain came back online just in time to hear Tony say something about biting.

"...like the fact that I bite?"

Steve meant to deflect, really truly he did. But his brain-to-mouth filter obviously still wasn't working properly because what came out of his mouth sounded a lot like flirting.

'_Paragon of Purity?' _he asked said brain. '_Seriously? That's what I come up with on short notice? I'm such a dork!'_

Except, maybe not, because Tony was flirting right back, and holding his mouth open, obstensively to showcase his teeth, but more likely to make Steve's mind go... Exactly where it went, actually.

Investigate with his _tongue_, really?

Well, he didn't have to be told twice.

Steve surged forward and initiated a kiss, which was slightly awkward since Tony already had his mouth open, but true to his reputation Stark got with the program quick.

He mentally congratulated himself on the use of the term "get with the program" before suddenly the feeling of claws tearing through his shirt caught his attention. Steve supposed that was only fair. Technically speaking, Tony wasn't wearing any clothes at all.

"Jarvis, let the others back into my suite. Keep them restricted there, but I want them _out of here_," Tony said. Well, the last part he growled.

Right. Steve had forgotten about them actually. His lips were covered in lots of little cuts from Tony's teeth, though whether Tony had nipped at him purposefully or that was just a side effect of kissing him was a tossup. Either way, the little kisses he left along Tony's throat and collar bone left smears of his blood. The possessiveness and satisfaction that surged through him at the sight might should have been worrying. Oh well. He slid down into the water in an effort to get closer. Grabbing Tony's jaw to guide their lips back together, Steve spared a passing thought for consequences and the fact that he really, _really_, didn't care about them in that moment.

"Oh, holy- What happened to your _shirt_ Rogers?"

That wasn't him or Tony, their mouths were occupied. Tony was now sort of distracted glaring over his shoulder at the interloper, but at least this time the kissing hadn't ceased. Was that Phil? Steve pulled away, still sort of dazed. Tony took the opportunity to bare his teeth and growl possessively.

"'S'at Phil?" Steve asked, rather than turning around. Tony's claws were poised warningly against his movement.

Deciding to take the silence as a yes Steve resigned himself to the fact that really, deciding not to care about consequences had just been tempting fate.

"Stark do you have- You know what? Nevermind. Doesn't matter. _Doesn't matter._ You will be filling out forms later pertaining to the fact that apparently the world can't only go a little crazy, so you two are now a thing."

Tony licked some of Steve's blood off his lips.

"Can I word it like that?"

Steve could picture Coulson throwing his hands up in the air in defeat.

"Fine. Whatever. We can discuss this," a pause where Steve imagined the agent gesturing awkwardly in their direction, "after we deal with whatever the hell is going on down in Texas. Avengers Assemble."

Tony pouted, but apparently his human mind won out because he released Steve and the tub began to drain.

"...You have a tail. You have a tail, and I just saw Captain America kissing a guy, and I am never skipping my morning coffee again."

Steve wondered if an impromptu make out session in a pool tub constituted being a thing.

"Tony, are we a thing?" Dagnabbit brain-to-mouth filter!

Oh. Oh, Tony was blushing. Maybe the lack of filter wasn't so terrible.

"You're cute when you blush." Nope, back to being a bad thing.

"AVENGERS ASSEMBLE!"

Oh, right. Guess they would have to wait and discuss the thing-thing later. Hopefully with more kissing. Though maybe not in the tub next time.

Get it together. Hero thoughts. Crises to investigate, people to save, etc.

This was going to be a long mission.


End file.
